1. Field
Embodiments relate to s localized surface plasmon resonance sensor using a chalcogenide material and a method for manufacturing same.
2. Description of the Related Art
Localized surface plasmon resonance is a phenomenon occurring when a collective oscillation of free electrons in a material is restricted inside a structure whose dimension is smaller than the wavelength of incident light. Since the resonance wavelength at which localized surface plasmons resonance is induced is very sensitively dependent on particle size and shape, change in surrounding medium, or the like, a biochemical sensor that can be utilized in the field of medicine, environment, etc. may be embodied using localized surface plasmon resonance. For example, Korean Patent Publication No. 10-2011-0042848 discloses an optical biosensor based on localized surface plasmon resonance.
As described in Korean Patent Publication No. 10-2011-0042848, precious metals such as gold (Au), silver (Ag) and copper (Cu) are frequently used to induce localized surface plasmon resonance. However, since the resonance wavelength of the localized surface plasmon resonance is usually in the visible region when such precious metals are used, only the change in the surrounding medium sensitive to light in the visible region can be detected.
The air coming out of the human lungs contain various biomarkers allowing diagnosis of diseases of individuals. But, since the wavelength allowing detection of the biomarkers is usually in the mid-infrared region, there is difficulty in detecting the biomarkers with the existing localized surface plasmon resonance sensors using precious metals.
To overcome this problem, efforts are made to broaden the resonance wavelength range by modifying the structure of the precious metal materials. However, the modification of the structure of the precious metal materials is not easy and it is much more favorable to choose other materials that operate well in the infrared region in terms of cost. Such materials may be semiconductor materials that exhibit properties comparable to those of metals in the infrared region although the density of electrons or carriers is smaller than that of the precious metals. For this reason, studies are carried out to change the resonance wavelength using doped semiconductor material. But, the doping process is complicated.
Meanwhile, it is of great importance to process a source material to have precise patterns in order to obtain resonance signals at wanted wavelength region using the localized surface plasmon resonance sensor. For this, electron beam (e-beam) lithography is employed for nanostructures and photolithography is employed for larger structures.
However, since these top-down processes are complicated and expensive, they are not suited for applications where a lot of inexpensive sensors are required such as biological or ecological detection. Although bottom-up type self-assembling processes are attempted to overcome this problem, it is difficult to obtain the desired patterns accurately.